1. Field of the Invention
The present invention relates to reducing radiation dose in X-ray Computed Tomography (CT) scanning by dynamic beam aperture control, and more specifically, to reducing radiation dose in X-ray CT scanning using collimators that can dynamically control the beam aperture.
2. Background
The annual number of CT exams has already surpassed 70 million in the US and this number is expected to increase even further. Although the radiation from CT exam is generally agreed to be weak, with a very small probability of causing cancer to patients, when this small probability is applied to tens of millions of CT exams, the total number of affected people can be quite significant. In fact, the controversial study of Brenner estimates that 0.4% to 2.0% of all new cancer cases may be attributed to CT radiation. In addition to this study, other studies claim that even though CT exams only make up 12% of all diagnostic radiological exams, the CT exams are responsible for over 45% of radiation exposure. While one may question the relevance of these statistics, one cannot deny the fact that ionizing radiation can be hazardous to your health and unnecessary exposure to radiation must be avoided at all times.